1. Field of the Invention
The invention relates to an anhydride compound, and more particularly, to a siloxane-containing trianhydride, a polymer obtained by performing a polymerization reaction using the siloxane-containing trianhydride as raw material, a liquid crystal alignment agent and a liquid crystal alignment film containing the polymer, and a liquid crystal display device having the liquid crystal alignment film.
2. Description of Related Art
In recent years, in various flat panel display devices, the liquid crystal display device has become the mainstream product in the market due to advantages such as small size, thin and light frame, power save, low power consumption, and good display quality.
The operating principle of the liquid crystal display device is based on the adjustment of voltage applied on the liquid crystal display device to change the arrangement of liquid crystal molecules. As a result, the polarization direction of light passing through the liquid crystal molecules is influenced such that the liquid crystal display device shows a change in brightness. In particular, the basic structure of the liquid crystal display device includes two transparent electrically conductive substrates. Liquid crystal is injected between the substrates, and a polarizer is added to the outside of each of the two substrates. Moreover, to arrange the liquid crystal molecules at a predetermined tilt angle in a specific direction, a layer of liquid crystal alignment film is coated on each of the two substrates, and rubbing is performed by applying pressure with a soft cloth such as cotton or nylon such that a nano-scale trench is left on each of the films. As a result, liquid crystal molecules can be arranged in each of the trenches in a fixed and uniform direction via an interaction force with polymers of each of the films such that a stable tilt angle is achieved.
The liquid crystal alignment agent material forming the liquid crystal alignment film can be a polymer such as polyamic acid, polyimide, polyester, or poly-organosiloxane, wherein polyimide is the most used liquid crystal alignment agent material due to properties such as chemical stability and thermal stability.
Since the demand for display quality of the liquid crystal display device is constantly increasing, the development of the material of the liquid crystal alignment agent is also becoming more important.